Remove retired courses and child courses from Course Admin Modal Same As dropdown

[natalynyu]

This PR removes the retired and child courses from the Course Admin Modal's Same As dropdown. A new API method, getActiveParentCourses, was added to get all of the non-retired, non-child courses, and these courses are directly passed into the Course Admin Modal via a prop called parentCourses.

This PR also fixes tests that broke as a result of merging new changes from develop.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] I have run eslint on the code
• [x] I have added JSDoc for all of my code (where applicable)
• [x] I have added tests to cover my changes.

Priority:

• [x] Normal
• [ ] High

Related Issues:

Fixes #651

[codecov[bot]]

Codecov Report

Merging #668 (60ee624) into develop (e59e8e2) will decrease coverage by 0.02%. The diff coverage is 90.32%.

:exclamation: Current head 60ee624 differs from pull request most recent head ac570e9. Consider uploading reports for the commit ac570e9 to get more accurate results

@@             Coverage Diff             @@
##           develop     #668      +/-   ##
===========================================
- Coverage    94.14%   94.13%   -0.02%     
===========================================
  Files          196      197       +1     
  Lines         4612     4637      +25     
  Branches       568      570       +2     
===========================================
+ Hits          4342     4365      +23     
- Misses         150      152       +2     
  Partials       120      120              

Impacted Files	Coverage Δ
...rc/server/courseInstance/courseInstance.service.ts	100.00% <ø> (ø)
src/server/report/report.service.ts	93.24% <ø> (ø)
src/server/course/course.service.ts	91.17% <78.57%> (-8.83%)	:arrow_down:
src/client/api/courses.ts	100.00% <100.00%> (ø)
src/client/components/pages/CourseAdmin.tsx	93.33% <100.00%> (-4.92%)	:arrow_down:
...rc/client/components/pages/Courses/CourseModal.tsx	87.85% <100.00%> (-0.12%)	:arrow_down:
src/common/dto/courses/ActiveParentCourses.dto.ts	100.00% <100.00%> (ø)
src/server/course/course.controller.ts	94.64% <100.00%> (+0.30%)	:arrow_up:

... and 3 files with indirect coverage changes

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more